/*
    * Copyright 2014 The Netty Project
    *
    * The Netty Project licenses this file to you under the Apache License,
    * version 2.0 (the "License"); you may not use this file except in compliance
    * with the License. You may obtain a copy of the License at:
    *
    *   https://www.apache.org/licenses/LICENSE-2.0
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
   * License for the specific language governing permissions and limitations
   * under the License.
   */
  package io.netty.example.spdy.server;
  
  import io.netty.channel.ChannelHandlerContext;
  import io.netty.channel.ChannelPipeline;
  import io.netty.handler.codec.http.HttpObjectAggregator;
  import io.netty.handler.codec.http.HttpServerCodec;
  import io.netty.handler.codec.spdy.SpdyFrameCodec;
  import io.netty.handler.codec.spdy.SpdyHttpDecoder;
  import io.netty.handler.codec.spdy.SpdyHttpEncoder;
  import io.netty.handler.codec.spdy.SpdyHttpResponseStreamIdHandler;
  import io.netty.handler.codec.spdy.SpdySessionHandler;
  import io.netty.handler.codec.spdy.SpdyVersion;
  import io.netty.handler.ssl.ApplicationProtocolNames;
  import io.netty.handler.ssl.ApplicationProtocolNegotiationHandler;
  
  /**
   * Negotiates with the browser if SPDY or HTTP is going to be used. Once decided, the Netty pipeline is setup with
   * the correct handlers for the selected protocol.
   */
  public class SpdyOrHttpHandler extends ApplicationProtocolNegotiationHandler {
  
      private static final int MAX_CONTENT_LENGTH = 1024 * 100;
  
      protected SpdyOrHttpHandler() {
          super(ApplicationProtocolNames.HTTP_1_1);
      }
  
      @Override
      protected void configurePipeline(ChannelHandlerContext ctx, String protocol) throws Exception {
          if (ApplicationProtocolNames.SPDY_3_1.equals(protocol)) {
              configureSpdy(ctx, SpdyVersion.SPDY_3_1);
              return;
          }
  
          if (ApplicationProtocolNames.HTTP_1_1.equals(protocol)) {
              configureHttp1(ctx);
              return;
          }
  
          throw new IllegalStateException("unknown protocol: " + protocol);
      }
  
      private static void configureSpdy(ChannelHandlerContext ctx, SpdyVersion version) throws Exception {
          ChannelPipeline p = ctx.pipeline();
          p.addLast(new SpdyFrameCodec(version));
          p.addLast(new SpdySessionHandler(version, true));
          p.addLast(new SpdyHttpEncoder(version));
          p.addLast(new SpdyHttpDecoder(version, MAX_CONTENT_LENGTH));
          p.addLast(new SpdyHttpResponseStreamIdHandler());
          p.addLast(new SpdyServerHandler());
      }
  
      private static void configureHttp1(ChannelHandlerContext ctx) throws Exception {
          ChannelPipeline p = ctx.pipeline();
          p.addLast(new HttpServerCodec());
          p.addLast(new HttpObjectAggregator(MAX_CONTENT_LENGTH));
          p.addLast(new SpdyServerHandler());
      }
  }